Water-duct pipe for preventing landslides

ABSTRACT

A water-duct pipe for preventing landslides: a water-duct pipe having a head at one end and a number of water inlet holes along the whole length is driven into the ground, and employed with a set of additional pipes connected consecutively and larger in bore than the water-duct pipe and a set of driving bars having a suitable diameter to fit to the water-duct pipe and connected consecutively, so that the water-duct pipe may be settled in the underground water layer while protecting it from clogging with earth. Although all the water inlet holes are closed by the driving bar inserted into the water-duct pipe during the driving operation, they may be opened, as required, by drawing the driving bar out of the water-duct pipe to permit underground water, if any, to flow.

tates Patent [1 1 Watanabe WATER-DUCT PIPE FOR PREVENTING LANDSLIDES [22] Filed: Dec. 21, 1973 [21] Appl. No.: 427,109

[76] Inventor:

[30] Foreign Application Priority Data Oct. 23, 1973 Japan 48-118565 [56] References Cited UNITED STATES PATENTS 216,042 6/1879 Le Grand et a1. 175/19 468,343 2/1892 Holland 175/19 674,191 5/1901 Allen et al. 175/19 1,200,119 10/1916 Keeler 6l/72.7 1,210,187 12/1916 Marquiss 6l/72.7 2,126,575 8/1938 Ranney 175/318 2,136,151 11/1938 Parrish 61/11 1 Sept. 2, 1975 2,186,364 1/1940 Carswell et a1. 61/63 2,383,496 8/1945 Nebolsine 3,261,412 7/1966 Lob 6l/53.7

FOREIGN PATENTS O'R APPLICATIONS 1,124,940 8/1968 United Kingdom 6l/53.5

Primary Examiner-Paul R. Gilliam Assistant Examiner-Alex Grosz Attorney, Agent, or Firm-Saul Jecies 5 7] ABSTRACT A water-duct pipe for preventing landslides: a waterduct pipe having a head at one end and a number of water inlet holes along the whole length is driven into the ground, and employed with a set of additional pipes connected consecutively and larger in bore than the water-duct pipe and a set of driving bars having a suitable diameter to fit to the water-duct pipe and connected consecutively, so that the water-duct pipe may be settled in the underground water layer while protecting it from clogging with earth. Although all the water inlet holes are closed by the driving bar inserted into the water-duct pipe during the driving operation, they may be opened, as required, by drawing the driving bar out of the water-duct pipe to permit underground water, if any, to flow.

7 Claims, 7 Drawing Figures PATENTEU 35? 2 75 sum 2 of 2 WATER-DUCT PIPE FOR PREVENTING LANDSLIDES BACKGROUND OF THE INVENTION The present invention deals with a water-duct pipe for preventing landslides, making it possible to discharge water present in excess in the earth in dangerous regions and keep the water content consistently at a stabilized level without decreasing the settling capacity.

Even though the causes of landslides are not clarified fully yet, it is commonly known that a landslide occurs accompanied by water flow in most cases, when the water content of the earth increases beyond the tolerable limit due to rain or other water. If landslides are caused in this way, it becomes necessary eventually to maintain the very strong settling capacity inherent in the earth by discharging its excessive water content automatically, so that a stabilized water content may always be maintained. It may be said that this is the best and the most effective means of preventing landslides in accordance with natural processes.

Water-duct pipes having a sharp conical head and a number of water inlet holes along the length have been employed in the past. They are driven horizontally or slightly inclined into the slopes at places where there is danger of landslides by connecting additional pipes until the preceding water-duct pipe reaches an appropriate layer. It is expected that the underground water v present there will be introduced into the water-duct pipe through the water inlet holes and discharged outside through the additional pipes. In fact, however, when such a water-duct pipe having a number of water inlet holes along its length is driven into the ground as it is, the earth pressed by the thrusting water-duct pipe invades it through the water inlet holes and settles there, eventually blocking the water inlet holes and the water-duct pipe. As a result, the pipe will not work as it is, even if it is driven into the proper layer. For this reason, when the driving operation is over, water is passed into the water-duet pipe by means of a pump so as to agitate this earth and wash it out onto the ground surface. This washing operation is repeated until the water-duet pipe inside is clean and its water inlet holes are opened. At the same time, a reservoir cavity may be formed around the water-duct pipe since the solid earth there may be disintegrated during the repeated washing. Thus, the underground water gathering in the cavity may be discharged outside through the water inlet holes, the waterduct pipe and the additional pipes. In this case, however. the amount of earth which may be agitated and discharged by each washing with a pump is very small and it takes considerable time and labor to complete the washing operation. Moreover, it becomes very difficult, particularly with increasing depth of the earth layer.

SUMMARY OF THE INVENTION Bearing the above defects of conventional water-duct pipes in mind, the purpose of the present invention is to provide an improved water-duct pipe for preventing landslides that makes it possible to consistently prevent the earth invading it through its water inlet holes during the driving operation and to settle it exactly at the underground water layer without fail by ascertaining the underground water flow required.

To this end, a water-duct pipe having a head at the end, a number of water inlet holes along its length and a connecting socket fixed at the other end is employed with a set of additional pipes connected consecutively with connecting sockets, and larger in bore than the said water-duct pipe, and a set of driving bars having a diameter suitable to fit the water-duet pipe bore and which can be connected consecutively by means of threads. During the driving operation, both the additional pipes and the driving bars are connected one by one as required and the rear end of the last driving bar is hammered. Thus, the water inlet holes of the waterduct pipe are closed by the inserted driving bar, preventing the invasion of earth into the water-duct pipe, while the underground water layer may be located without fail so as to fix the water-duct pipe there exactly by drawing the driving bar out of the water-duct pipe occasionally, as required, whereby the presence of an underground water layer may be determined by whether or not water flows out through the water-duct pipe and the clearance between the additional pipes and the driving bars.

The purpose, features and performances of the present invention are illustrated by the following explanation, referring to the appendix drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 represents a front view showing an example of the water-duct pipe of the present invention for preventing landslides.

FIG. 2 represents a perspective view showing the head as it is removed from the fixing end of the waterduct pipe.

FIG. 3 represents a front view of an additional pipe.

FIG. 4 represent a front view showing an additional pipe connected to the water-duct pipe.

FIG. 5 represents a front view of the driving bar.

FIG. 6 represents a partly cut front view showing the driving bar inserted into the water-duet pipe as it is driven into the ground.

FIG. 7 represents a partly cut front view showing the driving bars inserted after the additional pipe is connectcd to the water-duct pipe, as they are driven into the ground.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the water-duct pipe 10 of the present invention is shown in FIG. 1. The water-duct pipe 10 consists of a body 12, a head 14 fixed to the end and a socket 16 fixed to the other end. The body 12 is made of material such as steel pipe having a stipulated bore, length and rigidity and has a number of water inlet holes 18 bored along its whole length. As shown in FIG. 2, the head 14 has a ring 20 which is larger in bore than the body 12 and notched at the top end 22 to accept cross-like blades 24 having a sharp edge. It may be fixed entirely by setting the ring base 20 in the top end of the body 12. The socket 16 is to connect the additional pipe 28 to the body 12 as will be described below. Like the above head 14, it is made of a ring which is larger in bore than the body 12 and has internal threads 26 cut along the rear half to screw the top end of the additional pipe 28 into it. It may be fixed entirely by coupling the remaining half into the rear part of the body 12.

The said additional pipe 28 may be connected to the water-duct pipe by means of the socket 16 of the latter. Furthermore, it may be further connected consecutively to extend the pipe line as the water-duct pipe 10 is driven deep into the ground. For this reason, an appropriate number of additional pipes are prepared as a set for each water-duct pipe 10. As seen in FIG. 3, each additional pipe 28 is made of material such as steel pipe having a stipulated length and a larger bore than the body 12 of the said water-duct pipe 10 and has external threads 30 cut at the top to screw it into the internal threads 26 of the socket 16 attached to the base of the water-duct pipe 10. In addition, fixed at the rear end, it has a socket 34, which carries internal threads 32 to fit the said external threads 30. Thus it is possible to connect the additional pipe 28 to the water-duct pipe 10 or other additional pipes 28 by means of the internal threads 26, 32 of each socket 16, 34 and the external threads 30 at the top of each additional pipe 28. In such a manner, the pipe line may be extended as required by connecting additional pipes 28 consecutively to the water-duct pipe 10 as shown in FIG. 4.

As seen in FIG. 5, in order to drive the pipe line comprising the water-duct pipe 10 and the additional pipes 28 into the ground, the driving bar 36 is made of a very rigid material such as a round steel bar. It may be connected consecutively by means of threads 38 and its length is designed so that its rear end always protrudes appropriately beyond the rear end of the water-duct pipe 10 or the additional pipe 28 when it is inserted in the water-duct pipe 10 or the pipe line is extended with an additional pipe 28. Since each driving bar 36 has an outer diameter fitting the bore of the water-duct pipe 10, the water inlet holes 18 are closed by the circumference of the driving bar 36 when it is inserted into the water-duct pipe 10, while a clearance 40 exists when it is inserted into the additional pipe 28 which has a larger bore than the water-duct pipe 10 (see FIG. 7).

Upon driving the water-duct pipe 10 into the ground, therefore, the initial driving bar 36 is inserted into the water-duct pipe 10 so as to position the top at the base of the crushing blades 24 of the head 14 and an impact absorbing cap 42 is fixed by means of threads on the rear end of the driving bar 36 protruding beyond the rear of the water-duct pipe 10 so as to protect it from wear caused by the hammering. Then the crushing blades 24 are applied to the slope 44 in regions where there is danger of landslides while keeping the waterduct pipe horizontal or lowering it slightly, and it is driven in by hammering the impact absorbing cap 42. In this case, the water-duct pipe 10 overcomes the very strong resistance of the earth and thrusts into the ground, pushing the earth aside. The earth around the water-duct pipe 10 normally tends to invade it through the water inlet holes 18, but this invasion is prevented effectively, since these water inlet holes 18 are closed by the driving bar 36 inserted in the water-duct pipe 10 and since the direct resistance between the body 12 and the earth is significantly reduced as the body 12 passes earth which has already been disintegrated by the preceding head 14 which has a larger outer diame ter than the body 12 of the water-duct pipe 10.

The hammering is stopped just before the rear end of the water-duct pipe 10 is buried in the ground and the impact absorbing cap 42 is removed from the driving bar 36. Then, an additional pipe 28 is connected to the rear end of the water-duct pipelO as shown in FIG. 7,

while the driving bar 36 is also extended and the impact absorbing cap 42 is screwed again on its rear end to start the hammering. By repeating this process, the water-duct pipe 10 is driven in to the desired depth while connecting additional pipes 28 and driving bars 36 successively. After the water-duct pipe 10 has reached a certain depth, the driving operation is stopped occasionally, as desired, to open the water inlet holes 18 by drawing the driving bar 36 out of the water-duct pipe 10 somewhat beyond the length of the latter to ascertain whether or not underground water flows out through the opened water inlet holes 18, the water-duct pipe 10, and the clearance 40 between the additional pipes 28 and the driving bars 36. If underground water flows out, it indicates that the water-duct pipe 10 is already settled in the underground water layer and therefore the driving bars 36 are withdrawn completely to finish the operation. If not, it indicates that the waterduct pipe 10 has not yet reached the underground water layer and therefore the driving bar 36 is inserted fully again and the driving operation continued. In such a manner, the driving operation is carried out while periodically checking for the presence of the underground water layer. According to the present invention, therefore, it is possible to fix the water-duct pipe 10 without fail in the underground water layer while confirming its presence by a very simple method.

As stated above, a preferred example of the present invention has been explained. It is clear, however, that a number of modifications in the design and the method may be practiced without deviating from the principles of the present invention. Therefore, all such modified designs and methods which may produce effects substantially the same as that of the present invention by means of equipment substantially the same of equivalent to the present invention will be included in the scope of the claims.

What is claimed is:

1. A method of driving a drainage pipe for draining of excess ground water, comprising the steps of connecting a string of pipes, including a perforated drainage pipe having a driving head at its leading end, and at least one imperforate extension pipe connected to the trailing end of said drainage pipe and having an inner diameter larger than the inner diameter of said drainage pipe;

inserting into said string a driving rod having an outer diameter equal to said inner diameter of said drainage pipe so that said driving rod completely blocks the perforations thereof and forms within said extension pipe an annular axially extending clearance;

driving said string of pipes in substantially longitudinal orientation into the ground with said driving rod until said drainage pipe reaches a selected depth;

withdrawing said driving rod from said drainage pipe and into said extension pipe so that the perforations of said drainage pipe become unblocked and the interior of said drainage pipe communicates with said annular clearance;

observing the rear end of said string of pipes to determine whether an outflow of water occurs; and resuming driving of said string unless such outflow of water is observed.

2. A drainage pipe set for preventing landslides due to excess ground water, comprising a drainage pipe provided with perforations over substantially its entire length and adapted to be driven into the ground in a substantially horizontal orientation;

at least one imperforate extension pipe eoaxially connectable with a trailing end of said drainage pipe and having an inner diameter larger than the inner diameter of said drainage pipe;

connecting means for coaxially connecting said extension pipe to said trailing end of said drainage pipe; and

a driving rod insertable through said extension pipe into said drainage pipe into driving engagement with the latter, said driving rod having an outer diameter smaller than the inner diameter of said extension pipe to define therein annular clearance but equal to the inner diameter of said drainage pipe so as to completely block the perforations of the latter against clogging by the ambient soil, whereby the perforations of said drainage pipe are blocked by said driving rod against clogging by the ambient soil while said drainage pipe is being driven, and the position of said drainage pipe in relation to the ground water to be drained can be ascertained at any desired time by withdrawing said driving rod from said drainage pipe into said extension pipe to thereby unblock the perforations of said drainage pipe and communicate the interior of said drainage pipe with said clearance in said extension pipe, so that the gravity run-off or the lack thereof of water from a trailing end of said exten' sion pipe will indicate whether or not said drainage pipe has been driven to a depth at which water to be drained is present.

3. A drainage pipe set as defined in claim 2; further comprising an annular driving head; and coupling means for coupling said driving head to a leading end of said drainage pipe, said driving head having an outer diameter greater than that of said drainage pipe and an inner diameter substantially equal to the outer diame* ter of said drainage pipe, so that said leading end of said drainage pipe is insertable into said annular driving head.

4. A drainage pipe set as defined in claim 3, wherein the outer diameter of said annular driving head is substantially equal to the outer diameter of said extension pipe, so that when said pipes and head are being driven into the ground, said head and extension pipe will form in the soil around the drainage pipe of smaller outer diameter an at least partly soilfree annular clearance which surrounds said drainage pipe and aids in preventing the clogging of said perforations in said drainage pipe.

5. A drainage pipe set as defined in claim 4; and further comprising additional ones of said extension pipes similar to the first-mentioned one for extending the length thereof, and driving-rod. extension sections connectable with said driving rod for extending the length of said driving rod as the length of said extension pipe is being extended.

6. A drainage pipe set as defined in claim 3, wherein said driving head comprises a ring portion into which said leading end of said drainage pipe is insertable at one end of said ring portion, and a plurality of soilcrushing blades mounted on said ring portion at the opposite end of the latter.

7. A drainage pipe set as defined in claim 6, wherein said soil-crushing blades extend cross-wise of one another and transversely of said opposite end of said ring portion across the entire diameter of the same. 

1. A method of driving a drainage pipe for draining of excess ground water, comprising the steps of connecting a string of pipes, including a perforated drainage pipe having a driving head at its leading end, and at least one imperforate extension pipe connected to the trailing end of said drainage pipe and having an inner diameter larger than the inner diameter of said drainage pipe; inserting into said string a driving rod having an outer diameter equal to said inner diameter of said drainage pipe so that said driving rod completely blocks the perforations thereof and forms within said extension pipe an annular axially extending clearance; driving said string of pipes in substantially longitudinal orientation into the ground with said driving rod until said drainage pipe reaches a selected depth; withdrawing said driving rod from said drainage pipe and into said extension pipe so that the perforations of said drainage pipe become unblocked and the interior of said drainage pipe communicates with said annular clearance; observing the rear end of said string of pipes to determine whether an outflow of water occurs; and resuming driving of said string unless such outflow of water is observed.
 2. A drainage pipe set for preventing landslides due to excess ground water, comprising a drainage pipe provided with perforations over substantially its entire length and adapted to be driven into the ground in a substantially horizontal orientation; at least one imperforate extension pipe coaxially connectable with a trailing end of said drainage pipe and having an inner diameter larger than the inner diameter of said drainage pipe; connecting means for coaxially connecting said extension pipe to said trailing end of said drainage pipe; and a driving rod insertable through said extension pipe into said drainage pipe into driving engagement with the latter, said driving rod having an outer diameter smaller than the inner diameter of said extension pipe to define therein annular clearance but equal to the inner diameter of said drainage pipe so as to completely block the perforations of the latter against clogging by the ambient soil, whereby the perforations of said drainage pipe are blocked by said driving rod against clogging by the ambient soil while said drainage pIpe is being driven, and the position of said drainage pipe in relation to the ground water to be drained can be ascertained at any desired time by withdrawing said driving rod from said drainage pipe into said extension pipe to thereby unblock the perforations of said drainage pipe and communicate the interior of said drainage pipe with said clearance in said extension pipe, so that the gravity run-off or the lack thereof of water from a trailing end of said extension pipe will indicate whether or not said drainage pipe has been driven to a depth at which water to be drained is present.
 3. A drainage pipe set as defined in claim 2; further comprising an annular driving head; and coupling means for coupling said driving head to a leading end of said drainage pipe, said driving head having an outer diameter greater than that of said drainage pipe and an inner diameter substantially equal to the outer diameter of said drainage pipe, so that said leading end of said drainage pipe is insertable into said annular driving head.
 4. A drainage pipe set as defined in claim 3, wherein the outer diameter of said annular driving head is substantially equal to the outer diameter of said extension pipe, so that when said pipes and head are being driven into the ground, said head and extension pipe will form in the soil around the drainage pipe of smaller outer diameter an at least partly soilfree annular clearance which surrounds said drainage pipe and aids in preventing the clogging of said perforations in said drainage pipe.
 5. A drainage pipe set as defined in claim 4; and further comprising additional ones of said extension pipes similar to the first-mentioned one for extending the length thereof, and driving-rod extension sections connectable with said driving rod for extending the length of said driving rod as the length of said extension pipe is being extended.
 6. A drainage pipe set as defined in claim 3, wherein said driving head comprises a ring portion into which said leading end of said drainage pipe is insertable at one end of said ring portion, and a plurality of soil-crushing blades mounted on said ring portion at the opposite end of the latter.
 7. A drainage pipe set as defined in claim 6, wherein said soil-crushing blades extend cross-wise of one another and transversely of said opposite end of said ring portion across the entire diameter of the same. 